A strike by Bay Area Rapid Transit (BART) unions is paralyzing San Francisco and surrounding areas. It has left some 400,000 daily riders stranded or forced to drive, which has clogged highways and increased traffic delays. The Bay Area Economic Council estimates the cost in lost economic activity at $73 million per day.

Few indicators show the unions and management coming back to the bargaining table anytime soon. The sticking point is salary and benefits.

In most parts of the country, public employee strikes are illegal. Yet, in California they are legal under the Meyers-Millias-Brown Act. (They are also legal in Illinois, where 26,000 teachers went on strike last fall). Yet, public sector union leaders have often claimed that "the only illegal strike is an unsuccessful strike."

Public sector strikes are in many ways more damaging than those in the private sector. When employees walk off the job at a business, only the striking workers, the company, and its customers and suppliers are affected. The rest of the economy continues humming along.

In government, however, labor unions can hold the public hostage. Therefore, even President Franklin Roosevelt, a friend to organized labor, could say, "A strike of public employees ... looking toward the paralysis of government by those who have sworn to support it is unthinkable and intolerable."

The number of public sector strikes has declined dramatically since the 1970s, but when they happen, they are enormously damaging. In 2009, there were only five major work stoppages involving a mere 13,000 workers, according to the Bureau of Labor Statistics.

Yet, recall the 2005 pre-Christmas strike by the Transportation Works Union Local 100, which operates the subways and buses in New York City. The illegal strike disrupted holiday shopping and travel, costing the city millions.

Public sector strikes are part of the larger issue of how government workers unions reduce productivity and efficiency.

Rigid work rules enshrined in collective bargaining contracts reduce the discretion of managers to assign or transfer workers to tasks for which they are best suited. Management is also prevented from rewarding high performers, or disciplining and dismissing poor performers. In many jurisdictions, management has been emasculated.

Stanford political scientist Terry Moe studied the restrictiveness of teachers unions contracts. He found that, as teacher contracts become more laden with rules, they push student achievement down, especially for minority students.

Such work rules offer great job security for workers, but at the price of retaining some people who are often not very good at their jobs. The movie "Waiting for Superman" noted that each year one out of every 57 doctors loses their medical license and one out of every 97 lawyers is disbarred. But only one out of every 1,000 teachers is fired for performance reasons.

If having the best teachers in the classroom is a key to improving schools, union contracts are an obstacle to be overcome.

Salary schedules and seniority rules make the pace of advancement in the public sector glacial compared to the private sector. Talented people with a tolerance for risk are likely to be repelled by government work. It appeals more to those who crave stability, predictability, and regularity.

Consequently, there is a "brain drain" at the top end of the government work force, as many of the countrys most talented people opt for jobs in the private sector where they can be richly rewarded for their skills.

Public sector unions have also fought tooth and nail against the privatization of public services. They have done this even in areas such as sanitation where the tasks are well-defined, easy to observe, and obtainable from private suppliers.

All told, government costs more but does less. And the costs of state and local services have outpaced those of private services over the last decade.

When one combines union constraints on efficiency with the increasing pension and health-care costs of public workers, which can crowd out other government services, the result pleases no one across the political spectrum: Greater spending troubles conservatives; providing fewer services vexes liberals.

The BART strike is another sign of unionized government working against itself.